If Christ had not risen from the dead, what would the disciples have developed as Christianity? A religion about love and forgiveness, perhaps, but not about resurrection and a sure promise of Eternal life from a Resurrected human. I don't think the disciples would have been brave enough to start any religion.
But in fact, 20 centuries ago, they saw the risen Jesus Christ --and there was no stopping the news --and the boldness of their claim. They knew what they had seen --and believed their eyes. If Jesus rose from the dead, then everything He said --and everything the first century followers wrote --is worthy of our study. And I have no compelling reason to disbelieve their testimonies.
"God is not willing that any should perish, but that all should come to repentance and have eternal life."--the Bible